A5010123390- Stellar, planetary, and galactic studies
- Astronomy and Astrophysical Research
- Galaxies: Formation, Evolution, Phenomena
- Astrophysics and Star Formation Studies
- Astronomical Observations and Instrumentation
- Adaptive optics and wavefront sensing
- Scientific Research and Discoveries
- Astro and Planetary Science
- Gamma-ray bursts and supernovae
- Astrophysical Phenomena and Observations
- Horticultural and Viticultural Research
- Phase Equilibria and Thermodynamics
- Biocrusts and Microbial Ecology
- Astronomical and nuclear sciences
- Bee Products Chemical Analysis
- Radioactive contamination and transfer
- High-pressure geophysics and materials
- Spectroscopy and Chemometric Analyses
- SAS software applications and methods
- Plant Water Relations and Carbon Dynamics
- Nuclear physics research studies
- Pulsars and Gravitational Waves Research
- Dark Matter and Cosmic Phenomena
- Soil and Environmental Studies
Universidad Andrés Bello
2018-2023
Federal Research Centre Coal and Coal Chemistry
2021
European Southern Observatory
2011-2016
Universidade de São Paulo
2015
Scuola Internazionale Superiore di Studi Avanzati
2004-2008
In the current ΛCDM cosmological scenario, N-body simulations provide us with a universal mass profile, and consequently equilibrium circular velocity of virialized objects, as galaxies. this paper we obtain, by combining kinematical data their inner regions global observational properties, rotation curve disc galaxies corresponding distribution out to virial radius. This extends results Paper I, concerning luminous Sb–Im spirals, edge galaxy haloes.
Recently an increasing number of studies were devoted to measure the abundances neutron-capture elements heavier than iron in stars belonging Galactic Open Clusters (OCs). OCs span a sizeable range metallicity -0.6<[Fe/H]<+0.4), and they show light similar disk same age. A different pattern is observed for heavy elements. large scatter Ba, with most showing [Ba/Fe] [Ba/La] overabundant respect Sun. The origin this overabundance not clearly understood. With goal providing new observational...
We derived elemental abundances in 27 Cepheids, the great majority situated within a zone of Galactocentric distances ranging from 5 to 7 kpc. One star our sample, SU Sct, has distance about 3 kpc, and thus falls poorly investigated region inner thin disc. Our new results, combined with data on very central part Galaxy taken literature, show that iron, magnesium, silicon, sulfur, calcium titanium LTE abundance radial distributions, as well NLTE distribution oxygen reveal plateau-like...
We find a new Tully–Fisher-like relation for spiral galaxies holding at different galactocentric radii. This radial Tully–Fisher allows us to investigate the distribution of matter in optical regions galaxies. relation, applied three samples rotation curves galaxies, directly proves that: (i) velocity spirals is good measure their gravitational potential and both curve's amplitudes profiles are well predicted by galaxy luminosity, (ii) existence dark component, less concentrated than...
Barium is a neutron-capture element that, in open clusters, frequently overabundant with respect to iron. A clear explanation for this still missing. Additionally, its gradient across the Galactic disc poorly constrained. We measure abundance of yttrium and barium using synthetic spectrum method from UVES high-resolution spectra eight distant namely Ruprecht 4, 7, Berkeley 25, 73, 75, NGC 6192, 6404 6583. The was estimated non-local thermodynamic equilibrium approximation. confirm that...
We derive the disk masses of 18 spiral galaxies different luminosity and Hubble Type, both by mass modelling their rotation curves fitting SED with spectro-photometric models. The good agreement estimates obtained from these two methods allows us to quantify reliability performance very accurate stellar mass-to-light ratio vs color (and mass) relationships.
A robust classification of Cepheids into their different sub-classes and, in particular, between classical and Type II Cepheids, is necessary to properly calibrate the period-luminosity relations for populations studies Galactic disc. are, however, very diverse, classifications based either on intrinsic (period, light curve) or external parameters (e.g., [Fe/H], |z|) do not provide a unique classification. We want ascertain two HQ Car DD Vel, that are sometimes classified as Cepheids. To...
The Seminar "Dark Matter in Galaxies" was delivered, within the Dark Awareness Week (1-8 December 2010) at 140 institutes 46 countries and it followed by 4200 people. A documentation of this worldwide initiative is http://www.youtube.com/watch?v=AOBit8a-1Fw. reference presentation, prepared a coordinated pool leading scientists field, available to speakers. In response feedbacks suggestions, we upgraded "Presentation Review" which provide here Explanatory Notes, link .pptx file, some image...
The chemical composition of 28 Population II Cepheids and one RR Lyrae variable has been studied using high-resolution spectra. W Vir stars (with periods longer than 8 d) is typical for the halo thick disc stars. However, BL Her variables 0.8–4 drastically different, although it does not differ essentially from that belonging to globular clusters. In particular, sodium overabundance ([Na/Fe] ≈ 0.4) reported most these stars, Na–O anticorrelation also possible. evolutionary tracks a...
We present high signal-to-noise ratio spectroscopy of 15 emission-line galaxies cataloged in the KPNO International Spectroscopic Survey, selected for their possession equivalent width [O iii] lines. The primary goal this study was to attempt derive direct-method (Te) abundances use constraining upper-metallicity branch relation. spectra cover full optical region from ii]λλ3726,3729 [S iii]λλ9069,9531 and include measurement iii]λ4363 13 objects. From these spectra, we determine abundance...
We present an overview of the VISIR upgrade project. is mid-infrared imager and spectrograph at ESO's VLT. The project team comprised ESO staff members original consortium: CEA Saclay ASTRON. plan based on input from user community with goal enhancing scientific performance efficiency by a combination measures: installation improved hardware, optimization instrument operations software support. cornerstone 1k Si:As Aquarius detector array (Raytheon) which has demonstrated very good...
We present the results of a pilot project designed to study distribution dark matter haloes out very large radii in spiral galaxies. As dynamical probe we use their rotation curves and motions population satellite In this stage, observed seven late-type galaxies about same luminosity M_R ~ -22 (and approximately mass). investigate kinematics these galaxies, radial angular satellites. Using VIMOS at VLT, carried spectroscopic survey 14' x fields each around isolated galaxy. obtained...
Abstract We have investigated the stellar light distribution and rotation curves of high‐luminosity spiral galaxies in local Universe. The sample contains 30 high‐quality extended H α I curves. disk scale‐length these objects was measured or taken from literature. find that outermost parts disks massive objects, agree with Universal Rotation Curve (Salucci et al. 2007), however a few show divergence (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
We have analyzed 10 high-resolution spectra of Type II Cepheids with periods less than 3 days. find that they clearly separate into two groups: those near or slightly below solar metallicities, and [Fe/H] between −1.5 −2.0. While the former are usually called BL Her stars, we suggest latter be UY Eri stars. The subclass appears to similar short period variables in globular clusters Galactic Halo. Globular > −1.0 almost never Cepheids.
We present a dynamical analysis of the galaxy cluster AC114 based on catalogue 524 velocities. Of these, 169 (32 per cent) are newly obtained at European Southern Observatory (Chile) with Very Large Telescope and VIsible MultiObject spectrograph. Data individual galaxies presented accuracy measured velocities is discussed. Dynamical properties derived. obtain an improved mean redshift value z = 0.31665 ± 0.0008 velocity dispersion |$\sigma 1893^{+73}_{-82}\ {\rm km\,s^{-1}}$|. A large...
The European Southern Observatory (ESO) is preparing to upgrade VISIR, the mid-IR imager and spectrograph at VLT. project team comprised of ESO staff members original consortium that built VISIR: CEA Saclay ASTRON. goal enhance scientific performance VISIR facilitate its use by community. In order capture needs user community, we collected input from users means a webbased questionnaire. line with results internal study plan calls for combination measures: installation improved hardware,...
Context. The mass-metallicity relation (MZR) is a powerful tool to constrain internal physical processes that drive the chemical evolution of galaxies. However, construction this carried out with field star-forming galaxies in big data surveys where environmental effects are either negligible or not studied detail. Aims. We study role galaxy clusters MZR and its at z = 0.317 members AC114 (ABELL S1077). purpose work understand how both dynamical events modify cluster. Methods. Spectroscopic...
We study the role of galaxy clusters in mass-metallicity relation by using a sample galaxies belonging to AC114 (z=0.317) cluster. The data was taken from archival VIMOS-MOS spectroscopy estimate gas-phase metallicities strong-line methods. On other hand, obtained DECaLS DR10 and VIKING DR4 ESO surveys were used photometric masses. found that passive dominate population cluster center, whereas star-forming members tend be located outside this region. constructed MZR latter indicates SF have...
In this work we perform the photometric analysis of globular cluster system (GCS) giant elliptical NGC4696, which is brightest member Centaurus, a rich and dynamically young galaxy cluster. We obtained deep Magellan 6.5 m/MegaCam (g', r', i') photometry, with identified sample 3818 stellar clusters around NGC4696 that were analyzed in context possible interactions its assembly history. After carefully modeling subtracting light, used selection criteria based on shape, colors, magnitudes to...
Globular Clusters are remarkable witnesses of their host galaxy’s interaction and merger history. Our aim is to perform the photometric analysis Cluster System giant elliptical NGC 4696, brightest member Centaurus, a rich dynamically young galaxy cluster. We obtained deep Magellan $6.5$ m/MegaCam ($g'$, $r'$, $i'$) photometry, with which we identified sample $3818$ stellar clusters around 4696 that analyzed in context possible interactions its assembly After carefully modeling subtracting...
ABSTRACT We investigate the mass–metallicity relation (MZR)for galaxies in Abell cluster AC114 from 7 h of VIMOS/MR data collected at European Southern Observatory-Very Large Telescope 2009. The dynamical analysis completed our previous paper allowed us to select members, whose spectra are here analysed with stellar population synthesis models. Active and passive identified based on presence/absence [O ii] λ3727, iii] λλ4959, 5007 and/or Hβ emission lines, depending galaxy redshift. find...
We present a detailed study of the structural properties four gravitationally lensed disk galaxies at z=1. Modelling rotation curves on sub-kpc scales we derive values for mass, reference dark matter density and core radius, angular momentum per unit mass. The derived models suggest that curve profile amplitude are best fit with component similar to those local spiral galaxies. stellar also has length scale, but substantially smaller masses than similarly luminous in universe. Comparing...
For eight distant open clusters, namely Ruprecht 4, 7, Berkeley 25, 73, 75, NGC 6192, 6404, and 6583, we determined the yttrium barium abundances using UVES, VLT spectra (ESO, Chile). The stars of one young cluster (Ruprecht 7) demonstrate significant overabundance(∼0.55 dex) that can not be due to determination error. We have considered Ba abundance errors LTE approach, saturation lines, synthetic observed line fitting, causes overabundance associated with Galactic disc enrichment or origin...
Our research on the age-metallicity and mass-metallicity relations of galaxies is presented compared to most recent investigations in field. We have been able measure oxygen abundances using direct method for objects spanning four orders magnitude mass, probing last 4 Gyr galaxy evolution. found preliminary evidence that metallicity evolution consistent with expectations based obtained low resolution stellar spectra resolved Local Group galaxies.